A Chiral [3]Rotaxane Comprising Achiral Bis-macrocyclic and Dumbbell-Shaped Components.

In this study, we synthesized a molecularly chiral [3]rotaxane comprising a calix-bis-crown ether (as the macrocyclic component) and two unsymmetrical dialkylammonium salts (as dumbbell-shaped components) without any chirality in any of the individual components. Chiral high-performance liquid chromatography was used to separate the enantiomers, which were characterized by circular dichroism spectroscopy. Density functional theory calculations gave an insight into the absolute configuration of each [3]rotaxane.